Fuel stoker



March 30, 1937. s. M. DARLING 2,075,274

FUEL STOKER Filed June 13, 1954 5 Sheets-Sheet 1 S. M. DARLING FUEL STOKER March so, 1937.

5 Sheets-Sheet 2 Filed June 15, 1934 2 izveni'arz March 30,1937. s. M. DARLING FUEL STOKER Filed June 13, 1934 5 Sheets-Sheet 3 flor'ngy March 30, 1937. s. M. DARLING FUEL STOKEB Filed Julie 13, 1934 S Sheets-Sheet 4 v March 30, 1937. s. M. DARLING FUEL STOKER 5 Sheets-Sheet 5 321ml! .n l l l l lfir l l lIHHHHHHE 1522972507 mueZ7 .HHHHHHH Filed June 13, 1934 Patented Mar, 30, 1937 PATENT OFFICE FUEL STOKER Samuel M. Darling, Oak Park, Ill., assignor to Darling Automatic Stoker 00., a. corporation of Illinois Application June 13,

3 Claims.

The present invention is directed generally to a novel and improved construction of a fuel stoker of the portable type which is capable of being automatically or manually controlled.

The primary object of the present invention is to provide a simple, compact and eflicientlypperated portable type of fuel stoker.

A further object of the invention is to provide a novel and improved construction of fuel 10 stoker with means for automatically and evenly distributing the fuel on the fire bed.

A still further object of the invention is to provide a novel and improved construction of fuel stoker in which a rotor feed is provided which performs the double function of discharging the fuel into the firebox and furnishes a sufiicient current of air in delivering the fine coal dust into the firebox so that the same is burned in suspension.

A still further object of the invention is to provide a novel and improved fuel stoker in which the blades of the rotary feeder are hinged and in addition thereto, one of the blades is formed of a flat surface while the others have various degrees of curvature so as to effectively raise the coal stream in its delivery to the distributor.

A yet further object of the invention is to provide a novel and improved fuel stoker in which an adjustable bottom is provided in the coil chute for raising or lowering the delivery of the coal stream.

These and other objects are accomplished by providing a construction and an arrangement of the various parts in the manner hereinafter described and particularly pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a top plan view of a fragmentary portion of a boiler firebox (partly shown in crosssection) with my improved fuel stoker positioned in operative position with respect thereto;

Fig. 2 is a cross sectional view taken on the broken line 2-2 in Fig. 1;

Fig. 3 is an enlarged fragmentary view of the driving connections for my improved fuel stoker;

Fig. 4 is a cross sectional view taken on the line 44 in Fig. 3;

Fig. 5 is a cross sectional view taken on the line 5-5 in Fig. 1;

Fig. 6 is an enlarged fragmentary cross-sectional view of the rotary feeder;

Fig. '7 is an enlarged fragmentary perspective View of the fuel spreader;

Fig. 8 is a perspective view of the driving connections for oscillating the spreader;

1934, Serial No. 730,407

Fig. 9 is an enlarged detailed view showing the adjustable plate for raising or lowering the fuel stream; and

Fig. 10 is a bottom plan view of the same.

The primary feature of the present invention is to provide a'novel, compact and portable type of stoker to automatically and continuously feed the fuel into the fire box of a furnace in a uniform and. evenly spread manner over the fire so as to secure the maximum efliciency from the 0 fuel. The invention also contemplates the-control for the amount of fuel fed to the firebox by manual or automatic means, the latter of which may be controlled by well known arrangements such for example as the boiler pressure or by thermostatic control at some selected point.

In illustrating one form of my'invention, I have shown the same in connection with a conventional form of boiler, afragmentary portion of which is generally indicated by the reference character II. This boiler II is provided with the usual firebox l2, grate I 3 and front wall It. The inner walls of the firebox are provided with the usual refractory material generally indicated by the reference character IS. The front wall H of the furnace is provided with the usual fuel doors is and ash doors ll.

My improved portable stoker comprises a box like main frame generally indicated by the reference character l8, which is suitably mounted on four caster wheels l9, so that the same may be removed from or positioned in operative position in front'of the firebox. Mounted in the box like main frame structure l8 is a hopper, generally indicated by the reference character 20, which is in substantially the form of an inverted pyramid with the apex thereof supported substantially in the center of the main frame l8.as shown in Fig. 2 of the drawings. Mounted in suitable bearings in the main frame, adjacent the apex of the hopper is a shaft 2| to which two spaced apart sprocket wheels 22 are secured. Extending from one side of the hopper is an elevator housing, generally indicated by the reference character 23. The bottom of this housing forms an extension of one of the bottoms of the hopper and is relatively narrow as compared with the width of the hopper proper as clearly indicated by reference to Fig. 4 of the drawings. Mounted in suitable bearings, in a housing 23, is a shaft 25. Secured to the 50 shaft 25 within the housing and spaced with respect to each other, are two sprocket wheels 26. Trained about these sprocket wheels 26 and the lower sprocket wheels 22 are endless chains 21.

Connecting the corresponding links of each of the spaced apart chains 21 are elevator cleats 28. Mounted below the upper lap of the elevator chains is a supporting plate 23 which extends substantially the length of the elevator. Extending 5 over the upper portion of the elevator belt and extending to a point short of the bottom of the hopper is a shield or housing 30. Positioned below the delivery end of the elevator housing 23 is a rotor and fan housing 3|. Connecting the delivery end of the elevator housing 23 with the rotor and fan housing 3| is a discharge spout 32. (See Figs. 3 and 3.) Mounted on top of the elevator.

housing 23 is a variable speed transmission mech- 7 animal generally indicated by the reference charl5 acter 33. Mounted on the shafts 35 and 42 within 25 anism 33 through the sprocket wheels 36 and 31 secured respectively to the motor shaft and shaft 35. These sprocket wheels are geared together by a chain 33. Mounted adjacent the motor 34 in suitable bearings 33 is a supplemental drive 80 shaft 40. Secured to one end of the shaft 4|! is a large sprocket wheel 4| which in turn is operatively driven by a sprocket wheel 44 secured to a shaft 42 of the variable speed transmission mechanism 33. The sprocket wheels 4| and 44 are geared together by the chain 45. The speed of the elevator may be manually controlled or automatically controlled by the steam pressure or thermostatically. This elevator is driven through the shaft by means of the sprocket wheel 45 which 40 is geared to and operatively drives a chain 41 trained about a sprocket wheel 48 secured to the shaft 2 outside the elevator housing 23. The variable speed drive mechanism isprovided with the usual operating lever 49 to which the usual 45 connections may be made for either thermo statically controlling the feed of the fuel or for controlling the feed of the fuel by the boiler pressure.

One of the primary features of the present in- 5 vention includes in addition to a novel means for distributing the fuel evenly over the fire bed, also a novel means for delivering the fuel to the spreader with a sufiicient blast of air so that the fuel or coal dust is delivered to the firebox in 55 such a manner that it is burned in suspension.

This novel arrangement includes a rotor, generally indicated by the reference character 50, which comprises a shaft 5| mounted in suitable bearings located in the opposite sides of the rotor housing 3|. The shaft 5| is driven by the shaft 35 through the medium of a sprocket wheel 35 secured to the shaft 35 and a sprocket wheel 38' secured to one end of the shaft 5 I. These sprocket wheels are geared together by a chain 31. Se- 65 cured to the'shaft 5| are spiders 52. Secured to the periphery of these spiders is a cylindrical screen 53. Pivoted outside the screen and to each of the arms of the spiders 52 are blades 54, 55, 56 and 51. The swinging blade 54 is a flat blade, 70 while the blades 55, 55 and 51 are of gradual increasing curvatures. These various types of curved blades have a tendency to raise the stream of the fuel in its delivery to the spreader hereinafter described. Arranged about the axis of the 75 shaft 5| on each end of the rotor housing 3| are four equally spaced apart openings 53. These openings are arranged in the rotor housing within the periphery of the rotating screen 53 and permit the rotor to draw air inwardly so as to furnish a draftfor current of air in the delivery of the fuel and dust being discharged against the spreader, thereby permitting the fuel dust to be burnt in suspension within the firebox. Extending tangentially from the rotor housing 3| is a fuel discharging chute, generally indicated by the reference character 53. Mounted in a depressed recess59' and extending tangentially from the bottom curved portion of the rotor housing 3| is an adill-stable spring plate 53 which has one end thereof secured to the housing by means of rivets 5| and the free end thereof bent downwardly as shown at 52. This free end extends through a, slot 53 and is adjustable with respect to the bottom by a set screw 34. This adjustable plate 6|) permits the operator to raise or lower the heighth of the fuel stream in accordance with the type of fuel being discharged in the fuel box. In other words, when the fuel has a considerable quantity of larger lumps it is desirable to raise the fuel stream to secure a more effective spread of the fuel on the fire bed.

Another essential feature of the present invention includes the novel fuel spreading device which under most circumstances, may be satisfactorily used as a stationary spreader while under certain other conditions, I deem it advisable in order to secure more satisfactory and uniform spread of the fuel in the firebox to oscillate the same. oscillatable distributor, generally indicated by the reference character 55. This oscillatable distributor comprises a normally horizontal shaft or bar portion 68 which has a downwardly projecting stud 51 on which it is journalled in a socket 68 of a bearing support, which in turn, is secured to the top of the chute 53. This horizontal bar portion 63 has a right angularly and vertically extending arm 53 to which is secured or formed integrally with, three sets of distributor blades, generally indicatedv by .the reference character's 10, 1| and 12. The upper pair of blades diverge forwardly andoutwardh! in the arc of a relatively small circle, while the second set or pair of blades diverge forwardly and outwardly on a relatively larger arc of a circle while the third set or pair of blades, which are the lowermost ones diverge forward and outwardly on a still larger curve or are of a circle. From an examination of Figs. 2 and '1 of the drawings, it will be observed that the relativelyshort blades are 10- cated at the top where thegreater portion of the fuel .being discharged is of thelighter variety while the intermediate pair of blades 1| and lower pair of blades 12 are positioned substantially at the center of the mouth of the distributing chute. At this point, these relatively larger curved blades efiect a uniform distribution of the major portion of the larger lumps of fuel. It will also be noted that there is a substantial opening between the lower pair of blades 12 and the bottom of the chute in order to permit the relatively largelumps to be discharged without being effected by the spreader so that the same may be discharged to the furthermost end of the firebox. The other end of the bar 56 is provided with a fiat portion, as shown at 13. Located in the end of this flat portion is a longitudinally extending slot 14 to which is slidably and pivotally connected by means ofa pin 15, an arm 16. The crank arm '15 is formed integrally with or secured to the This novel spreading device comprises an lower end of a vertical bar 11. The lower end of the bar 11 is provided with a stud 11' which is pivotally mounted in a bearing support 18 secured to the upper portion of the fuel chute 59. The upper end of the-bar I1 is bent at right angles as shown at 18 and journaled by means of a pin 19' in a bracket 19. One end of the bracket 19 is secured to the elevator housing 23. The bent portion of the bar 11 extends laterally to form an arm 80, the outer end of which is provided with a longitudinally extending slot 82 which is adapted to pivotally and slidably receive a pin 83 secured to one end of a pitman connection 84. The other end of the pitman connection is pivotally connected by means of a pin 85 to a crank '86 secured to one end of the upper elevator shaft 25.

The operation of my improved fuel stoker is as follows:

Let us assume that the fuel stoker is positioned in operative position so that the fuel discharge spout 59 extends into the opening in the firebox in the manner disclosed in Figs. 1 and 2 of the drawings and that the electric motor is connected to operatively drive the operating parts thereof in the manner previously described. In this connection it will be understood that the variable speed drive mechanism may be manually controlled or automatically controlled by the steam pressure or thermostatically in any well known manner, and as the elevator elevates the fuel from the hopper it is discharged from the delivery end of the elevator into the rotor which is connected to be driven at a relatively high speed so as to deliver the fuel streamwith suflicient velocity to delivery the larger lumps of fuel at the furthermost end of the fire bed. In so doing, it will be understood that the rotor in addition to functioning as a discharge means for delivering the fuelinto the fire bed, performs the additional function of a fan for drawing the air axially through theopenings in the side walls of the rotor housing and thereby deposits the fuel dust into the firebox where it is burned in suspension. As this action is taking place, the fuel spreading device 65 is oscillated from one side to the other by the operative connections 84, 80 and 11 as clearly shown in Fig. l of the drawings, to effect a uniform and even distribution of the fuel in the fire bed. reason of the position, length and different curvatures of the various pairs of blades, as well as the oscillating action of the spreader, a uniform and even distribution of the fuel discharged through the chute is secured.-

While in the above specification I have de- In this connection it will be observed by scribed one embodiment which my invention may assume in practice, it will of course, be understoodthat modification may be made without departing from the spirit and scope of the invention as expressed in the following claims:

What I claim is my invention and desire to secure by Letters Patent is:

1. A fuel stoker for a firebox comprising a frame, a hopper in the form of an inverted pyramid mounted on said frame, an endless elevator. mounted in said hopper, a rotor mounted below the delivery end of said elevator, said rotor com-- prising a plurality of differently curved blades, a housing encasing said rotor for receiving the fuel from said elevator, a chute extending from said housing into said firebox there being openings adjacent the axial center of said rotor in said housing through which air is drawn by said rotor for effectively discharging the fuel in the stream under air pressure through said chute, and a plurality of pairs of differently curved blades located in the path of the stream of fuel for effecting a uniform distributing of the fuel in said firebox.

2. A fuel stoker for boiler firebox comprising a portable frame, a hopper mounted on said frame, elevating means mounted in said hopper, a rotary impeller located below the delivery end of said elevating means, a housing encasing said impeller and the delivery end of said elevating means, a discharge chute connected tangentially with said housing and extending into said firebox, and an automatically actuated osclllatable fuel spreader located at the end of said chute and including a plurality of pairs of differently curved blades mounted on a common pivot, said pairs located at different elevations with respect to each other for evenly distributing the fuel in said firebox.

3. A fuel stoker for a firebox comprising a frame, a hopper mounted on said frame, means mounted in said hopper for elevating the fuel from said hopper, a housing positioned below the delivery end of said elevating means and adapted to receive fuel therefrom, a rotary impeller mounted .in said housing below said elevating means for discharging the fuel from said housing,

SAMUEL M. DARLING." u 

